Yoshimura introduces “ST-1M Camshaft” for Z900RS/CAFE!
In particular, it continues to accelerate overwhelmingly, feeling the weight of the torque from the mid RPM to the peak.The Z900RS ST-1M camshaft, its “M” in the product name is the abbreviation of “machining”. The camshaft for the Z900RS is reduced in weight by machining in the middle throughout the whole shaft in large diameter. This improved both response and burden of camshaft itself and other related parts around.
*1 When using this product, be sure to use a BAZZAZ Fuel Controller. Without fuel adjustment, the camshaft will not achieve the expected performance.*2 Be sure to measure and adjust the tappet clearance and valve timing when installing.
Suggested BAZZAZ mapping can be downloaded from the YOSHIMURA JAPAN website. Please adjustment the mapping as guided.
[What is YOSHIMURA’s camshaft?]
■Unique cam profile settings
Yoshimura is designing a camshaft profile by their original expertise. The design of the profile starts with knowing the standard engine dimensions. Assume the engine rotational speed and characteristics you want to use, and then determine the characteristics of the profile of the Yoshimura camshaft. Then, the determined profile characteristics are expressed numerically.
The long-standing know-how of Yoshimura derives its own original cam profile by transforming ideas into numerical data.
The camshaft with this profile is produced experimentally and incorporated into the engine to see if it actually has the desired characteristics. If the characteristics of a camshaft aren’t the one expected, YOSHIMURA starts all over again from the beginning. After repeating this sequence of work, Yoshimura’s unique cam profile is derived.
■ Consistent production management
The Yoshimura machined Camshaft manages consistent production, including centering of camshaft materials. YOSHIMURA also committed to the material used to reproduce the profile designed, so that they machine their camshaft all in their factory.
The partial heat addition of the product is considered to damage the strain, deformation and strength of the camshaft itself, the Kamayama Overlay Shaping (welding at high temperature) is not performed. To make the camshaft’s hardness suitable for the engine, they select best heat treatment from various heating methods.
Consistent management of unique cam profile design + production. This is Yoshimura’s pride for the camshafts.
The following camshaft specification is derived from the design values of the camshaft. There may be a slight difference that is within the acceptable range for each lot due to manufacturing reasons.
The ST-1M can usually be assembled by bolt-on, it is recommended that you reset the valve timing for each vehicle if more accuracy is required.
Model Year: 2018-2019
Motorcycle Model: 2BL-ZR900C
Engine Model: ZR900BE
・This item is scheduled to release in October 2019.
MAX LIFT (mm): IN 8.3mm/EX 7.0mm
1 mm DURATION (°) : IN 227°/EX 221°
Standard Tappet Clearance (mm): IN 0.15mm/EX 0.25mm
Original Source[ YOSHIMURA ] (*Japanese)